In the packaging industry, many products are packed in cardboard boxes or cartons for shipping. Often, one end of the box, namely the bottom, is sealed shut before the box is filled, and after the box is filled, the open top end of the box usually has end and side flaps that are folded inwardly and downwardly. The box can be sealed by applying glue to the inside of the mating surfaces of the folded flaps prior to them being folded shut, or by applying tape to the outside of the flaps after they have been folded shut.
In many cases, the boxes are uniform in size, so providing apparatus that will fold the flaps and apply adhesive or tape thereto is not particularly difficult to do. The apparatus can be adjusted to suit the known width and the height of the boxes and there is usually no problem running the boxes through the case sealer once it has been adjusted properly.
However, sometimes the boxes are of different sizes coming down the same conveyor line. In these instances, a random case sealer is required, wherein the apparatus for folding the box flaps and applying adhesive or tape thereto adjusts automatically to suit the size of the box.
In prior art random case sealers, various sensors have been used to try to determine the exact size or position of the boxes entering the case sealer, and numerous actuators or other adjustment mechanisms, together with suitable control devices, have been used to adjust the position of the various folding and sealing components to suit the position and size of the box being sealed. A difficulty with the prior art devices, however, is that the boxes are often misshaped or underfilled or overfilled, so that they are not uniform in shape, so the sensors often cannot determine the optimum position adjustments. The result is that the boxes get jammed in the apparatus shutting down the packaging line.
Another difficulty with some prior art case sealers is that they tend to be slow, in that if the boxes are of different sizes, a new box cannot enter or proceed through the case sealer until the previous box has cleared the sealer and the controls have been reset to be ready to receive the new box. An example of this is shown in U.S. Pat. No. 3,894,380 issued to Poulsen.